If you haven't yet purchased the WDTV-live, I'd suggest looking at the alternatives first e.g. Asus, Patriot and the new PopBox, which is supposed to be available in the US later this month. Plus the Boxee Box is coming out later too.
After living with a WDTV-live for ~4mo, I love the concept (I use it as a DVR for downloaded content), but IMHO, the WDTV implementation is sorely lacking.
It's clear the box was rushed to market for the Christmas season, and despite 14 iterations of the production software (iirc, .10 was the first release, .24 is the latest), a number of critical bugs have yet to be resolved;
1. The device is notoriously temperamental in regards to seeing network shares (esp. for XP users). After a reboot, mine is quick to see media servers, but sometimes takes a while to see network shares hosted on the same physical server.
2. The infamous "lost network connection" bug is becoming increasingly irritating; the box will lose the connection (wired in my case), halting playback, necessitating a reboot and several-minute wait to re-acquire the network shares. I'm seeing this ~2x per week.
Despite living with these deficiencies, I also find the user interface extremely basic and during playback, the RW/FF functions are quite choppy, so if you get interrupted, it's hard, if not impossible to return to the spot where the interruption began.
I hope that WD will address these problems, but in the meantime, I'm looking forward to the reviews of the PopBox. If favorable I'll consider getting one, even though we can't get NetFlix